Method for creating an index and method for searching an index

A method for searching an index which obtains a corresponding document name from a word serving as a key by using an index with document names associated with words contained in the documents,

• wherein document identification numbers and word identification numbers are assigned to document names and words, respectively, to uniquely identify them, and
• wherein a value with a document identification number concatenated with a word identification number is used as the key.

A method for searching an index which constitutes an index with document names associated with words contained in the documents by a plurality of subindexes, assigns document identification numbers and word identification numbers to document names and words, respectively, to uniquely identify them, and obtains a corresponding document name from a word serving as a key by using an index registered in a subindex in a two-dimensional array position referenced by a value determined by applying a hash function to a document identification number and a word identification number,

• wherein a search by a plurality of words is performed in such a way that groups are formed by the values obtained by applying a hash function to the identification numbers of the words and the subindexes are searched on a group basis.

A method for searching an index which constitutes an index with document names associated with words contained in the documents by a plurality of subindexes, assigns document identification numbers and word identification numbers to document names and words, respectively, to uniquely identify them, and obtains a corresponding document name from a word serving as a key by using an index registered in a subindex in a two-dimensional array position referenced by a value determined by applying a hash function to a document identification number and a word identification number,

• wherein an AND or OR search of a plurality of words is performed in such a way that subindexes for documents grouped by the values obtained by applying a hash function to document identification numbers are searched for the occurrence of each word and the AND or OR operation on the search results is performed.

A storage medium storing a program for having a computer create an index with keys and values associated, to search for a value from a specified key, in a format readable from the computer for execution,

• wherein said program constitutes an index to register sets of keys and values by a plurality of subindexes and stores the subindexes in two-dimensional array positions referenced by values determined by applying a predetermined function to the values to be registered and values determined by applying a predetermined function to the keys.

An index of a database in which sets of keys and values are registered,

• wherein said index is constituted of a plurality of subindexes, and
• each of said subindexes is stored in a storage medium position determined by a first value obtained by applying a predetermined function to a value and a second value obtained by applying a predetermined function to a key.